利用urljoin快速将url补全

如采集的url只有后一半如

./target/000001.html

./target/000002.html

./target/000003.html

./target/000004.html

from urllib import parse
houzhui = './target/000004.html'
url = 'http://pycs.greedyai.com/' 
url = parse.urljoin(url,houzhui)